PROJECT SUMMARY Sleep irregularity is highly prevalent and linked to downstream adverse cardiometabolic health outcomes, but the upstream drivers of sleep irregularity are not well characterized. Adverse health outcomes associated with irregular sleep timing mirror those linked to shift work, and irregular sleep may represent a driver of circadian misalignment and related disease in the general population. Notably, sleep timing is modifiable and could serve as an inexpensive, non-invasive way to promote health, but further research on environmental factors influencing sleep regularity is required to inform successful interventions. Understanding the environmental drivers and molecular markers of irregular sleep are critical gaps that would aid public health intervention and disease prevention efforts. The recent 2021 NIH Sleep Research Plan highlights research on the effects of environmental exposures on sleep and on epigenetic mechanisms underlying sleep and circadian health as top priorities. Therefore, to address these gaps in knowledge and stated research needs, I propose to apply acquired training in sleep epidemiology, chronobiology, and advanced statistical analysis and epigenetics to: 1) investigate which dimensions of light exposure impact sleep regularity and moderation by factors such as age and sex (K99), 2) develop biological markers of sleep regularity (K99), 3) validate and establish the temporality of resulting findings with prospectively collected data (R00), and 4) expand measurement of light and environmental factors with prospectively collected data (R00). My goal is to establish an independent research program centered around how light and other environmental exposures affect sleep and chronobiology in population health. This proposed study and career development plan logically builds upon my training in environmental health, vision research, and molecular epidemiology, to gain expertise in light data analysis and collection, sleep epidemiology, chronobiology, advanced statistical modeling, and omics integration. With expert mentored guidance provided by Dr. Tamar Sofer, Dr. Susan Redline, and Dr. Frank Scheer, I will establish a unique interdisciplinary research program focusing on the interactions of the light environment and sleep. This award will provide key training in four areas: 1) sleep epidemiology; 2) clinical chronobiology; 3) integration and analysis of high-dimensional light and actigraphy data with omics data; and 4) professional development. This data collected during the R00 phase will also provide a strong foundation for R01 applications. This support provided by this award will allow me to launch a novel independent research program and address inherent gaps in our understanding of the role of naturalistic light exposure on sleep health in the general population.

PROJECT NARRATIVE Irregular sleep is highly prevalent and linked to the development of adverse health outcomes, yet it is also highly modifiable, representing an important public health target. Here, we seek to characterize and validate dimensions of naturalistic light exposure that affect sleep regularity and blood-based markers of sleep regularity. This research has the potential to advance the field by investigating the contribution of environmental light, an important but underexamined exposure, to sleep health and identify relevant markers to inform sleep health in the general population.